Antifriction slipring device



o. A. KENDALL 3,514,653

ANTIFRICTION SLIPRING DEVICE Filed Jan. 21, 19 Fi Oakley A. Kendall INVENTOR.

BY M

United States Patent Olfice 3,514,653 Patented May 26, 1970 3,514,653 ANTIFRICTION SLIPRING DEVICE Oakley A. Kendall, Huntsville, Wash. (Rte. 1, Box 100, Dayton, Wash. 99328) Filed Jan. 21, 1969, Ser. No. 792,613 Int. Cl. H02k 31/00 US. Cl. 310-232 5 Claims ABSTRACT OF THE DISCLOSURE A slipring device including an insulated housing having laxially spaced cavities therein. A pool of mercury is contained in each cavity. An insulated sleeve axially extends through the housing and mounts a conductive disk in each cavity. When the shaft rotates, each disk is caused to continually rotate through a mercury pool. Electrical leads are connected between each cavity Wall and a respective disk so that electrical contact is achieved without frictional engagement.

The present invention relates to a slipring device for continuously conducting current to a rotor from -a source of electricity.

In the past, slipring devices have been designed using an intermediary conducting medium of liquid mercury. Generally these devices include a stationary housing supporting a bearing through which a shaft passes. Disks are mounted on the shaft and positioned so that they rotate in respective cavities formed inside the housing. The liquid mercury deposited in the cavities insures constant electrical contact between input terminals contacting the mercury, and output leads connected to the disks. Generally, such prior devices utilize a conductive housing or a conductive shaft as a terminal which is unsatisfactory and hazardous when operating with large voltage and current values.

In the present invention, neither the housing nor shaft is used as a conductor or a part of a power circuit. Electrical current is insulated by a non-conductive housing. Individual disks are used for internal transfer of power from each power line thereby substantially reducing the safety hazard of the prior art.

Further, the components of the present invention are cast or molded in half sections so that manufacture and assembly is facilitated. Because the housing is separable, one portion may be removed for assembly inspection without disturbing the shaft, bearings, or other mechanical parts.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a perspective cut-away view of a centrifugal heater-blower utilizing the present invention.

FIG. 2 is a longitudinal sectional view of the invention taken along a plane passing through section line 2-2 of FIG. 1.

FIG. 3 is a transverse sectional view taken along a plane passing through section line 33 of FIG. 2.

Referring to the figures and more particularly FIG. 1, there is illustrated a centrifugal heater-blower or thermal fan 8 of the type disclosed in my prior Pat. 3,211,891, issued on Oct. 12, 1965, with which the present invention may be associated.

The present invention is adaptable as an improved low friction, long wearing component that provides a continuous transfer of electrical energy to the rotating heater element constituting the fan blades of the blower, thereby causing the blower to emit heated air. The slipring device generally referred to by 10 is fastened by a bracket 12 internally to the blower motor housing 14. An electrical cable 16 having input power leads is received in the blower motor housing and is connected to input terminals on the slipring device. Output leads from the device are connected to heater element terminals 18 rotated relative to the housing 14. Thus, when power is supplied to the device through cable 16, continuous electrical power is transferred to terminals 18 so that the heater element constituting the fan blades are continuously energized during rotation of the blower shaft 20 upon which the device -10 is concentrically mounted.

Referring to FIGS. 2 and 3, the components of the device 10 include a cylindrical, non-conductive housing 22 which is suit-ably formed from symmetrical halves having an interface 24 extending diametrically along the entire axial length of the housing. In order to retain the half sections together, longitudinally disposed flanges 26 are clamped together at diametrically opposite sides of the housing by suitable fasteners 28.

Two generally cylindrically shaped and axially spaced cavities are formed in the housing as shown in FIG. 2. The ends of the housing are characterized by outwardly extending axial hubs 32. The shaft 20 passes through the hubs in concentric relation thereto. Each hub includes an interiorly formed recess 34 for receiving a bushing 36 therein. The bushing serves as a bearing along its radially inward surface 37 which contacts the shaft 20. An insulated sleeve 38 comprised of two longitudinal half sections is cemented to shaft 20 as indicated by 39. Reference numeral 42 represents the thrust bearing interface between sleeve 38 and each bushing 36.

For convenience, the components contained within only one cavity will be described although it will be understood that identical components are associated with the second cavity. The disk is denoted by 44 and includes a portion 48 extending from an axial hub 46 mounted on sleeve 38 and disposed centrally of its associated cavity 30. The disk 44 is preferably fabricated from carbon in the form of half sections. Annual recesses 50 are formed at the intersection of the disk portion and the hub. Keeper rings 52 are received within the recesses to retain the half sections of the disk together.

A bore hole 54 extends radially outwardly through shaft 20, sleeve 38, and an aligned segment of hub portion 46 through which an output lead is inserted. The stripped terminal portion of the lead 58 is engaged in the hub portion 46 as indicated by 62. Thus, electrical continuity between the leads 58 and 60 and the disk is established. A quantity of liquid mercury or other conductive liquid 64 forms a pool in each cavity 30 having a surface level approximately intermediate the radially outward wall of the cavity and the hub 46. A pair of input terminals or binding posts 66 are embedded within the housing, each including an inward end that just passes beyond the radially inward wall of the associated cavity 30 thereby effecting contact between the mercury and the binding post. Thus, with the housing disposed in a horizontal position, electrical paths between respective input terminals, mercury pools, disks, and output leads will be completed.

Referring to FIG. 2, a bore hole 70 is formed in shaft 20 adjacent the fan blade support 74 through which the output leads 58 and 60 exit. As shown in FIG. 1, the outer ends of leads 58 and 60 are connected to terminals 18 which provide electrical tap-off points for the heater element fan blades 78.

In operation of the blower, electrical power is provided to the blower motor (not shown) through cable 80. Electrical power is simultaneously fed to the slipring device which continually transfers the power to the heater element fan blades as the blower shaft and attached slipring components rotate. The result is a forced heated airflow from the exit port 82 of the blower.

Although the slipring device 10 has been described in the environment of a centrifugal heater blow or thermal fan, offering low friction and long wear because solid metal to metal contact is obviated, it will be appreciated that the invention is adaptable to other rotating machinery where sliprings, brushes and the like are now being utilized. Further, the present invention may be employed in lieu of prior art mercury filled slipring devices which do not exhibit the advantages of the present invention as set forth hereinbefore. Also, although the preferred embodiment has been described in terms of two line, single phase operation, it should be understood that the number of disks and associated components may be increased or decreased according to power supply arrangement and needs.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. A slipring assembly comprising a non-conductive housing having at least one cavity therein, each cavity containing a pool of conductive fluid, an insulative sleeve axially mounted in the housing, a conductor disk mounted on the sleeve for rotation therewith relative to the housing within the cavity and through the fluid therein, an input terminal post anchored to the housing and having an inward end contacting the fluid within the cavity, an input power line connected to the terminal post, and an output lead connected to the disk.

2. The assembly set forth in claim 1 wherein the nonconductive housing includes two mating sections having a diametrical interface, and fastener means removably holding said sections assembled.

3. The assembly set forth in claim 2 wherein the insulative sleeve includes two sections having a diametrical interface extending along the entire sleeve length, and a rotating shaft connected to the sleeve sections.

4. The assembly set forth in claim 3 wherein each conductor disk includes two mating sections having a diametrical interface extending along the entire axial length of the disk, the disk sections having mating hub elements, and keeper means engaging the hub elements for retaining the disk sections in abutment.

5. In combination with a rotor mounting an electrical element and a shaft made of electrically conductive material to which the rotor is connected, an anti-friction slip ring assembly for transferring electrical energy from an external source to the electrical element comprising a non-conductive housing enclosing at least one cavity through which the shaft extends, a pool of conductive liquid disposed within said cavity in radially spaced relation to the shaft, insulating means mounted on the shaft within the housing for electrically isolating the cavity from the shaft, a conductive disk mounted by the insulating means within the cavity for rotation with the shaft in continuous contact with the conductive liquid, stationary terminal means mounted by the housing in contact with the liquid for conducting current thereto from the external source, and conductor means extending through the shaft and the insulating means for electrically connecting the disk to the electrical element on the rotor.

References Cited UNITED STATES PATENTS 2,753,476 7/1956 Watt 3 lO-178 2,914,688 11/1959 Matthews 310-478 3,021,496 2/1962 Kenyon 31O-232 3,229,133 1/1966 Sears 310-178 MILTON O. HIRSHFIELD, Primary Examiner L. L. SMITH, Assistant Examiner U.S. Cl. X.R. 

